Positive Pay -- Alternate Name to be populated if exists else supplier name

Summary

Positive Pay -- Alternate Name to be populated if exists else supplier name

Content

We are populating supplier "Alternate name" on the checks if it exists and if alternate name doesn't exist then populating supplier name on the checks.

Requirement is to populate the same in the positive pay file.  So I added  below in the "DATA"  field of the positive pay file template but alternate name is not being populated in positive pay file.

If ALTERNATENAME IS NOT NULL THEN

ALTERNATENAME

ELSE

Payee

Any suggestions why this is not working or what is wrong here or how do I get this to work.